Its Pretty Easy
1:You must Have Mpack5(design Your own mission)
You Can Download It in GTA garage.
2:And Have Cleo 3 or Higher.
3:Extract My Dyom Missions In your GTA SA User File
4:Start The Game And Hit New Game And Design Your...
5ress Y and Load My Mission (Prison Break Story)
6:Enjoy
Hope That Helped.

Can you please give me links to get DYOM (MPack) 5 and also CLEO 4...
Without them, as you say, I cannot play the mission.
And I am a huge fan of Prison Break and think this is a great idea.
Can you/others also hep me to understand and instruct me on what to do? And how to play the mission.
E.g. What file goes where? What file to replace? What do I make copies of?
Thank You